Objective: To investigate the neurocognitive effectiveness of haloperidol, risperidone, and olanzapine in first-episode schizophrenia-spectrum disorders.

Method: This prospective, randomized, open-label study was conducted from February 2001 to February 2005. Data for the present investigation were obtained from a large epidemiologic and 3-year longitudinal intervention program of first-episode psychosis (DSM-IV criteria) conducted at the outpatient clinic and the inpatient unit at the University Hospital Marques de Valdecilla, Santander, Spain. One hundred four patients randomly assigned to haloperidol (N = 35), olanzapine (N = 30), or risperidone (N = 39) who completed clinical and cognitive evaluations at baseline, 6 months, and 1 year were included in the final analysis. Thirty-seven healthy individuals were also longitudinally assessed. A neuropsychological battery that comprised 9 cognitive domains was used. The contribution of clinical changes, concomitant medications, and the severity of motor side effects to cognitive changes was controlled. The main outcome measure was cognitive changes at 1-year follow-up.

Results: The 3 treatment groups showed a significant improvement in cognitive scores after 1 year. The differential cognitive effectiveness between antipsychotics was insignificant. The magnitude of cognitive changes was similar in the 3 treatment groups and controls, although a greater improvement on the Finger Tapping Test, Trail Making Test B, and Rey Complex Figure Test was found in the treatment groups. Clinical changes, use of concomitant medications, and the emergence of motor side effects did not significantly account for cognitive changes over time.

Conclusion: Haloperidol, olanzapine, and risperidone were equally effective in treating cognitive deficits of psychosis. The effect of practice clearly contributes to cognitive score improvements after treatment with antipsychotics. Our results provide important information regarding the practical utility of antipsychotic treatments to improve cognition and could have implications for developing novel approaches for cognitive pharmacotherapy in schizophrenia.